On Mon 2018-07-23T13:18:22-0600 Warner Losh hath writ: > In the absence of setting a local time for the leap > second, the offset is controlling and therefore it happens at UTC midnight, > since it's definitely and unambiguously defined in ITU-R TF 460-6 as such > (all known earlier revisions too, I believe was the conclusion when a > similar issue was raised years ago on this list, though I think -3 was the > oldest that could be found at that time).
We have managed to obtain scans of varying rattiness of all versions. More interesting than the versions themselves are the related recommendations (some since withdrawn) and the transcripts of the discussion in the voting sessions. Those give some clues into what had and had not been presented to the general assembly in order to motivate their approval of the new versions. E.g., from 1974 through 1997 the ITU-R recommeded using either UTC or TAI as appropriate. https://www.itu.int/rec/R-REC-TF.485/en CCIR Rec 460 had no details other than 1 second leaps. This original (version "0") Rec was reprinted in various places including by US NBS in Monograph 140, so it is online in scanned documents. The rules were worked out in CCIR Report 517 (Question 1/7, Resolution 53) by Study Group 7 during 1971-02-17/23. This put the leap second at UTC midnight. It is also reprinted in NBS Monograph 140. This was incorporated into Rec 460-1 by the CCIR general assembly between 1971-02-17/23 and remains the same in all subsequent revisions. CCIR and ITU-R documents mention UTC, UT[012], and TAI, and they refer the reader to other agencies for definitions of those terms. They do not mention local civil time, -- Steve Allen <[email protected]> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m _______________________________________________ LEAPSECS mailing list [email protected] https://pairlist6.pair.net/mailman/listinfo/leapsecs
